One poster, amfxc, received a reply from someone in TalkTalk's
CEO's office, Michael Hopkins. He said it was all down to
protecting people from child abuse images.

"We currently block URLs recommended by the Internet Watch
Foundation (IWF) that contain child abuse imagery. Due to the way
we block these links, we are aware that some users may experience
intermittent issues accessing some hosting sites for the days when
a sub-URL, or content that is being hosted on that site, has been
placed on the IWF list."

So the point is that when an illegal image is identified on a
very popular site, such as Imgur, the whole site can suffer, as
TalkTalk pushes all content through a single server in order to
filter the offending content. This allows the ISP to block the
particular URLs before the offending material is taken down, but
has the unintended consequence of throttling access to the whole
site.

A community executive on TalkTalk's customer forums said: "We do however know this is
very inconvenient for customers affected and we are working on an
improvement to how we block the IWF list that is intended to stop
this happening in the future. We hope this will launch very soon
and we will keep you updated with news."

The IWF issued a statement saying that it doesn't block
websites, but provides a list of URLs for companies to facilitate
URL blocking, but "not IP address or domain-level blocking".

Redditor Antagony contacted Imgur and received a response which
said that the image hosting site had "multiple issues with
TalkTalk, including this exact same one in the past, but they are
always unresponsive to our requests to work it out together".

"We have not seen this issue with any other ISP, UK or
otherwise," said the representative.

A spokeswoman told Wired.co.uk that Imgur had experienced a
"complete domain block" from TalkTalk at the end of October 2013,
which was lifted in November that year. The current issue of
throttling or "monitoring" has been ongoing through March, our
first user reports coming in on March 5. It is our understanding
that under 10 instances of child sexual abuse imagery were included
on the UK IWF watch-list, which prompted TalkTalk to throttle Imgur
as a domain, despite that the watch-list includes only specific
URLs."

She urged TalkTalk customers to "consider switching
ISPs if browsing Imgur at full performance is important to
them".

Given that Imgur is one of the top 100 sites in the world,
pulling in two billion image views and 100 million uniques per
month, it might be advised that TalkTalk works out way of blocking
illegal links that doesn't affect users' ability to load content at
speed.

Wired.co.uk has contacted TalkTalk and Imgur for comment.

Updated 21:00 01/04/2014: A TalkTalk spokesman
told Wired.co.uk: "In blocking access to links
identified by the IWF as containing child abuse imagery, it was
never our intention to cause customers any delay in accessing other
legal content hosted on the same domain. We apologise for this and
we are in the process of improving the way we block access to the
IWF list so this doesn't happen in future. This is absolutely a
high priority. We are working closely with the IWF and we have also
contacted Imgur directly. Users shouldn't currently be experiencing
issues accessing the site and we will continue keep customers
constantly updated as we have further developments via our
forum."